Raster is a data format consisting of regular grids of values, usually stored in an image-like format.

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FME - Raster Algebra and Multicriteria Analysis

I'm trying to use FME to do some raster algebra for some Multi-Criteria Analysis. At the moment, I have three rasters, all with the same extents and resolution: Slope, Hydro, and Infrastructure Mask. ...
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44 views

How can I preserve image quality when combining aerials of different resolutions?

I have two different rasters that were flown at different times during the same month. One has a resolution of 4-inches, the other has a resolution of 6-inches. Using ArcGIS tools, how can I combine ...
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1answer
403 views

GDAL TIF to JPG Creates Dark Image

I'm using the GDAL Raster>Translate to create JPGs from Georeferenced TIFs. The translation is working, but the resulting JPGs are significantly darker than the TIFs they are being created from. ...
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87 views

The difference when querying raster and vector

Hi everyone I have two queries have the same meaning but different results. Why is there a difference?. Queries are true? query 1: query 2:
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30 views

How to Separate Bands Through ModelBuilder [duplicate]

Q1: I have a .tiff file containing 365 bands. Each band represents a daily variable. I want to separate each band and save as a single .tiff file. In the end, I want to have 365 individual .tiff files....
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311 views

Is there a Raster2pgsql GUI?

Has anyone ever attempted to create a raster2pgsql gui (like the shp2pgsql gui). As I am sometimes lazy to use command line, this could be a very nice to have.
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1answer
1k views

Batch raster conversion

I want to do conversion from WCG to UTM for my 172 Raster, I can't use normal batch because I I can't re-arrange again the order of raster in Table of Content because the result are random name in ...
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32 views

what is the math behind rasterization? Doubt [duplicate]

In Figure 4 you can see how the overlap is not complete (marked with circles). What I would like to know which algorithm that QGIS uses the rasterization? What is your standard? Is there a percentage ...
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1answer
152 views

qgis's georeferencer renders my white map with a translucent blue tint, can I prevent this?

I'm running QGIS 2.0.1-Dufour on MacOSX and when loading a PNG or TIFF into qgis as a raster its always getting rendered with a blue tint. Here's what it looks like before being loaded into QGis's ...
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23 views

Overlay Shapefile and Raster layer in R [duplicate]

I have a raster layer with climate data from the north of Mexico, part of Canada and the US mainland. I am trying to restrict the climate data to only the zone of the US mainland. To do this I thought ...
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3answers
327 views

What is the math behind rasterization?

I'm taking the first steps in QGIS (version 2.2 Valmiera) and I am having some difficulties in knowing what mathematical criterion that QGIS uses when converting polygons (shapefile) to raster. I'm ...
11
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1answer
1k views

Leaflet rendering TileMill tiles in the wrong order

I'm stumped, and quite a lot of searching has turned up nothing helpful. I'm on the first step of what will ultimately be a map with three raster layers and three layers of markers (with controls to ...
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1answer
225 views

Symbology Stretch Multiple Raster

I need to change stretch of a raster using properties - Symbology to Minimum-Maximum like image bellow : Problem is I have about 172 raster, is there any way to make this automaticaly change? I ...
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2answers
222 views

How do I mask a raster in TileMill?

I've tried just about every single TileMill compositing operation on the vector and raster layers in question, and I have to admit that I can't figure it out: How the heck can I mask a raster with a ...
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1answer
74 views

r.series command in QGIS - timeseries

I am using r.series command in qgis. The command is performing correctly, but when I import input raster files, it creates a list in a random order. Sometimes the order of input rasters is essential ...
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136 views

Gdal_translate and transparent rasters in PDF

I am trying to make an application that creates geospatial pdf's from my website, but I am encountering problems with Gdal_translate and transparency of rasters. The setup that I am working up ...
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1answer
637 views

Clipping Rasters from Mosaic Dataset in their Original Coordinate System

I am building a large mosaic dataset that contains several hundred rasters, which are spread across three UTM zones. My goal is to be build a tool in ArcMap (most likely within model builder) that ...
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1answer
851 views

Is there a way to write single bands raster from multi-band layer faster in r?

I have 1000 multi-layer rasters and have to export each separate layer to a tif. Some friends recommended R to do the job. I used the following code: library(raster) namesVector<- c("layer1", "...
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1answer
141 views

How do I replace cell values of a raster using values of another raster with differing extent?

I have two rasters (raster1 and raster2). The raster1 extent is smaller than raster2. I want to replace the value of raster2 pixels using raster1 pixels. How can I replace the values?
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1answer
27 views

Setting Pixels Band Values

I have a single band RASTER of an area, in which I want to create 360 bands and then assign those bands values from a table. Is there a process for doing this?
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57 views

Rasterizing vector contour data: Python error message

would anyone know why qgis kicks up this error message (image attached) when using v.to.rast.attribute? the rasterise related to a contour set. i duplicated it twice to create 3 copies. the first ...
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1answer
162 views

Build a Raster GIS Web Application

We need to build a Web based GIS application for Raster data computation (analysis). All the maps are in form of raster images. We are failing from a week to find a proper tool which allows fetching,...
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166 views

Arcpy raster calculation producing random no data cell in output

I've been trying to get the raster calculation below to work using python: import arcpy from arcpy import env import os from arcpy.sa import * arcpy.CheckOutExtension("spatial") KSat_mm = "C:\\GIS\\...
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1answer
54 views

How to select a specific area (in a polygon form) determined by some value range in a raster band?

For example, I want create a vector layer with polygons that represents all areas where the elevation is between 500 and 600. Someone has any idea to help me? I'm using PyQgis 2.2.
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1answer
202 views

How to batch generate thumbnails of raster layers with R?

I have been using R to maintain a rather large stack of raster layers (over 700 layers of data for sub-Saharan Africa). Each layer looks as follows http://hcapi.harvestchoice.org/v2.0/core/?varCode=...
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1answer
193 views

QGis export part of map (box with coordinates) as raster

I would like to export a map of Switzerland (as part of googlemaps) to use as a background for a graph, but I need to know exactly where each corner of the map corresponds to (wrt spatial coordinates)....
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1answer
190 views

Export Stretch Function values - Arcpy

I'm looking for a way to export Stretch Function values from images that’s stored in a Mosaic dataset. Not values from the whole set, but specific stretch functions per image. The set is stored in ...
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68 views

Slope regions from elevation points using QGIS 2.0

I am using QGIS to create a layer of slope region polygons (e.g. less than 30% slope, 30-50%, more than 50% categories). My data comes from point elevations and I interpolated using SAGA b-spline ...
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1answer
299 views

DN value from raster to vector tool (QGIS 2.0)

I am using QGIS 2.0 to convert a DEM to vectors, then create polygons of zones of slopes. However, I am unsure of in what units my new "DN" column is. It has lost of precision of z-values from my ...
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83 views

Is it feasible to reclassify a raster which has been resampled/smoothed for display purposes?

Background: I have a Google Earth KMZ file which shows ground movements after an earthquake, arranged into discrete classes: From the KMZ file I'm able to download the original PNG images, which ...
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95 views

rasterize a geography polygon using postgis 2.1

I am still bit new to Postgis 2.1. I am trying to rasterize a polygon, meaning that I have a polygon of Syria and I want to create an empty raster that contains the shape and geography reference of ...
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2answers
955 views

Calculate Slope Between Pixels Through Time: A Time Series Trend Analysis

I have a 9 year weekly time series (~500 raster grids of equal cell size and extent). I'm interested in obtaining the regression line slope between pixels (Imagine stacking all 500 grids on top of ...
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265 views

Ecoregions shapefiles: subsetting, extracting and summarizing data from raster

I am attempting to subset and project an ecoregions shapefile from : EPA ECOREGIONS my data set is found here: SHAPEFILES and RASTER When I run this code, two major problems occur: 1) I cannot get the ...
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1k views

How to extract vectors from map using QGIS?

I am trying to extract building footprints from a raster map (as shown in the example below). Please note that the maps are out of copyright, have been scanned and georectified by a library and have ...
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136 views

Issues creating slope raster layer from a point layer

I'm trying to create a slope raster layer using QGIS 2.0 on Windows XP. I started with a points layer with the Z elevation attribute. I then used the interpolation plugin to create a DEM. But, ...
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1answer
131 views

Need to calculate values for a cell based on surrounding landscape

I have a raster file with the urban development of a county mapped out (values: 1=urban 0=not urban). I also have a raster file with several blocks of forested land, each block of land has its own ...
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1answer
315 views

Raster Calculator Syntax - ArcGIS

I'm trying to reclassify a raster based upon two criteria 1. Raster cell on "CBH" is less than or equal to 2 AND "footprint" is not null. Then output raster reclassifies any cell inside this criteria ...
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2answers
1k views

Replacing raster values in one raster with another raster in QGIS … how to?

I have a raster (DEM) and want to replace a few cell's values with the values from another raster in QGIS. I would have done this with the "over" tool in the raster calculator in ArcGIS. Specifics: ...
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1answer
52 views

Which format is more convenient to publish in Erdas Apollo?

I am from Bolivia and I need to publish some Satellite images in Erdas Apollo. My question is Which format is more convenient for publish in this software?, because I have Landsat5 TM images in TIFF ...
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90 views

MapServer: UV_ANGLE not calculated correctly?

I'm following this example given on the MapServer website. But the angle of the raster is incorrect: The data is my grib files is correct, and should not yield these perfect opposite directions. ...
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2answers
832 views

Minimum mapping unit for raster on ArcGIS

So I have this huge national wetlands raster and I'm trying to set a minimum mapping unit of 5 acres. Meaning I want to delete clusters of pixels that are smaller than 5 acres. But the raster's ...
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1answer
466 views

Iterative raster calculation script using NumPy arrays breaks after ~10 rasters, returns: “TypeError: Cannot create raster for numpy array.”

Here is my code: #Generate Cumulative Thresholds #5/15/14 import os import glob import arcpy import numpy as np #Enable overwriting output data arcpy.env.overwriteOutput = True ####################...
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2answers
1k views

Change detection with raster calculator

After applying the Diff operator of the raster calculator in arcgis to view changes in land use, would like to see the areas of increased and areas of decreased. This is possible using the raster ...
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105 views

How to draw rotated symbol RASTER type layer in Mapserver?

[PARTIALLY SOLVED]: I was on the wrong track I need to use a UVRASTER, see this part of the docs But doing leaves with with another question about how to get the angle correctly, please see this ...
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1answer
466 views

Raster calculation in for loop returning exit code -1

I've put together a python script that does some calculations on rasters by converting them to NumPy arrays, doing the math, then converting them back to Raster and applying all the same spatial ...
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85 views

How to get RasterToPolygon working

We have a process that is almost working except for this one call ... This is the one tool function that is requiring a FeatureClass and I found code that I thought would work. Unfortunately all I ...
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1answer
114 views

Passing RasterDataSource object to RasterData object in Javascript API?

I have a GP service that requires a RasterData object as input. The RasterData object should hold a RasterDataSource object, but I'm not sure of the syntax to connect these two classes. The API ...
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1k views

How do I display a raster “Background Value” as hollow for more than one set of RGB values?

I have two overlapping .ecw layers of the same area, though one is clipped in the middle, with a white edge. When I set the background value to 255,255,255, and define it as hollow, it only hollows ...
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75 views

PostGIS raster connection is not closed by MapServer

I'm using PostGIS raster in MapServer like this: TYPE RASTER DATA "PG:port=6432 dbname='mydb' user='postgres' password='1234' schema='public' table='truemarble' mode='2'" PROCESSING "CLOSE_CONNECTION=...
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1answer
74 views

R equivalent of GRASS r.grow?

What is a good R equivalent of the GRASS function r.grow? The closest I've been able to find is the script suggested by whuber in response to Creating randomly shaped clumps of cells in a raster from ...